(06) (7.1b-e) Suppose we are able to collect a random sample of data on economics majors at a large university. Further suppose that, for those entering the workforce, we observe their employment status and salary 5 years after graduation. Let SALES salary for those employed, GPA = grade point average on a 4.0 scale during their undergraduate program, with METRICS -1 if student took econometrics. METRICS -0 otherwise. a. Assuming By and B, are positive, draw a sketch of E(SAL GPA, METRICS) Be+ B,GPA+B,METRICS b. Define a dummy variable FEMALE - 1. if the student is a female: 0 otherwise. Modify the regression model to be SAL - B1+B,GPA+ B;METRICS+FEMALE+. What is the expected salary of a male who has not taken econometrics? What is the expected salary of a female who has taken econometrics c. Consider the regression model SAL-B + B,GPA + BMETRICS + 8,FEMALE + 82(FEMALEX METRICS) + What is the expected salary of a male who has not taken econometrics? What is the expected salary of a female who has taken econometrics? (Please note that actual numeric values are not required. Simply modify the equation depending on the relevant indicator variables), d. For the equation given in part c, assume that ,